I didn't think we HAD a constitution, but I agree- 52:48 result was an instant problem.
Oh- as far as I remember, 'referendum' isn't neuter second declension, but a gerund, 'The asking' which has no plural ending,
so 'referendums' is likely ( jury is still slightly out) to be the correct plural English form. Long time ago. ( Latin and my learning of it. Another gerund there,....( I think)....)